Apparatus for surfacing valve seats



July 23, 1940- H. G. MILLER 2,208,680

APPARATUS FOR SURFACING VALVE SEATS Original Filed Feb. 5, 1934 2 Sheets-Sheet l [N VEN T 0R July 23, 1940. H. G. MILLER APPARATUS FOR SURFACING VALVE SEATS Original Filed Feb. 5, 1934 2 Sheets-Sheet. 2

, BY m/ A TTORN YJ:

Patented July 23, 1940 UNITED `STATES APPARATUS FOB sUnr'Acmc VALVE scars Harry G. Miller, Denver, (Bolo.`

Original application February 709,686. bel' 28, 1935, Serial 20 Claims.

My invention relates to resurfacing valve seats.

One of the objects of my invention is to provide an improved means for resurfacing valve seats in which the resurfacing tool will be accurately centered.

A further object of my invention is to provide improved means for resurfacing valve seats of the type in which the valve moves outwardly in its seating movement, such as certain types of airplane motors.

A further object is to provide an improved means for resurfacing valve seats comprising the use of a tubular pilot through which part of the transmission for the resurfacing cutter extends.

A further object of my invention is to provide improved apparatus for resurfacing valve seats involving a gear reduction between the operating member and the resurfacing cutter.

A further object of my invention is to provide an improved means for resurfacing a valve seat which will make the seating surface gas-tight, thereby preventing the blow torch action of the hot gases which causes an abnormal rise in the temperature of the motor head, causes excessive gas and oil consumption, and impairs the eiciency of the motor performance.

Further objects will be apparent from the specication and claims.

This application is a division of my copending application Serial No. 709,686, filed February 5,

Fig. 2 is an axial sectional view showing theparts of Fig. 1 and, in addition, showing the use of a tool for cleaning and scraping the valve stem guide and coaxially counterboring the ends of the valve stem guide;

Fig. 3 is an axial sectional view showing a further step in my method including the installation of the cutter pilot and feed mechanism;

Fig. 4 is an axial sectional view showing a further-step of my method including the putting in place of the roughing cutter on the pilot and the connection therewith of the operating mechanism for the roughing cutter;

Fig. 5 is an axial sectional view showing a further step including the use of the :finishing cutter after the roughing cutter has done its work;

Fig. 6 is a transverse section on the line 6-6 of Fig. 5;

Fig. 7 is a transverse section on the line 1-1 of Fig. 5;

Fig. 8 is a transverse section on the line 8 8 5, 1934, serial No.

Divided and this application Decem- (Cl. Sil-12.5)

of Fig. 2, showing the cleaning and scraping shank; and

Fig. 9 is an enlarged sectional view showing the counterbored valve stem guide and p ilot.

Referring to the drawings in detail, and following the successive steps, the construction shown in Fig. 1 comprises a valve seat I and valve stem guide 2 of a known type of airplane motor, for use with a valve which seats by an outward movement. In use, the constant reciprocating movement of the valve stem in the guide causes this guide to become worn, particularly at the ends, forming a sort of bell mouth at each end of the valve stem guide. This wearing of the valve stem guide results in imperfect seating of the valve, permitting the leakage of gas with the consequent undesirable effects as pointed out above of increasing the motor head temperature, burning the valve seat, and excessive oil and gas consumption.

Heretofore it has been common, when it became necessary to resurface the valve seat, to iit the pilot into the worn valve stem guide to provide a centering means for the resurfacing cutter. Due to the irregular worn condition of the valve stem guide, the pilot would flt loosely and not be accurately centered with respect to the seat so that the seat itself would not be ground coaxially with the unworn portion of the valve stem guide and would not be resurfaced in a plane at right angles to the axis of the unworn portionv of the valve stem guide.

In order to provide for the pilot, I-provide a tool for cleaning and scraping the internal surface of the valve stem guide throughout its length and for counterboring both ends of the valve stem guide to provide an accurate centering for the pilot which in turn centers the resurfacing cutter.

This scraping and counterboring tool, shown in Fig. 2, comprises a cleaning and scraping shank 3 which extends throughout practically the entire extent of the valve stem guide, a counterboring portion 4 for effecting a counterbore at the outer end of the valve stem guide, and a counterboring portion 5 for effecting a counterbore at the inner end of the valve stem guide. The cleaning and scraping portion 3 has the general appearanceof a reamer but the contour of the scraping blades 6 of the reamer is circular in transverse section, as show-n in Fig. 8, so that no clearance is provided for these scraping blades and consequently there will be little or no cutting action on the internal surface of the valve stem guide but only a cleaning and scraping action suiiicient to clean land scrape the internal surface of the valve stem guide thoroughly.

A tool is chosen having a shank which will iit snugly in the valve stem guide so that the rotaaccurate centering of v ti'on of this scraping shank will effectively clean -the inner surface of the valve stem guide. Also,

due to the snug ilt of this scraping shank of the valve stem guide, it will serve to center accurately the tool with respect to the valve stem guide to cause the counterbores at the ends of the guide to be perfectly coaxial with respect to the unworn portion of th'e valve stem guide. The two counterboring portions are similar in nature, being in general of an end milling cutter type suitable for providing a cylindrical counterbore in each end of the valve stern guide. In order to adjustably limit the depths of the counterbore, stop collars 1 are provided which may be set at the desired points on the shank of the tool by means of set screws 8. These collars limit the depth of the counterbore by coming in contact with the ends of the valve stem guide.

A suitable operating handle 9 is provided having a bayonet joint connection III with the shank of the tool. The outer counterbore is effected by pressing inwardly on the operating handle as it is rotated and the inner counterbore is effected by pulling out on the operating handle as it is rotated..

Fig. 3 shows a further step in the method in which the counterboring and scraping tool is removed and the pilot and feed mechanism for the cutter is put in place. 'Ihis pilot and feed appar'atus comprises a pilot II having a tubular portion extending completely through the valve stem guide, an enlarged cylindrical arbor portion I2 having a force iit in the inner counterbore,

4a clamping sleeve I3 having threaded engagement with the outer end of the tubular pilot and having an annular shoulder portion, the end of which has a force fit with the outer counterbore, and a feed nut I4 having threadedengagement with the outer end of the clamping sleeve I3. Axial openings are provided through the feed screw I4 and clamping sleeve |'3 in alignment with the opening through the tubular pilot to provide for the insertion of an operating shaft for the cutter hereinafter referred to.

In putting the pilot and feed mechanism in place, the tubular pilot Il is separated from the clamping sleeve |3 and inserted into the valve stem guide 2 from the inside of the cylinder (see Fig. 5). The clamping sleeve I3 is then threaded onto the end of the tubular pilot and screwed up tight to bring the parts I2 and I3 into snug forced engagement with the counterbores in the valve stem guide respectively. This centers the pilot II with precision, insuring that the cutter will be coaxial with the unworn portion of the valve stem guide.

Fig. 4 shows the next step, which is the putting in place of the roughing cutter and the operating mechanism therefor. This roughing cutter mechanism comprises a cutter head I4 mounted for rotational and axial movement on the tubular arbor I2 of Fig. 3, an operating handle I5 for rotating a shaft I6 which extends through the tubular pilot and associated parts and gear reduction mechanism between this shaft I6 and the cutter head I4 to lessen the torsional strain on the shaft and provide increased torque for the cutter head. This gear reduction mechanism between the shaft and the cutter head (see Fig. 7) comprises a drive pinion I1 rotatable with the shaft I6, a plurality of pinions I8 surrounding and meshing with this central drive pinion, a supporting plate or spider I9 on which these pinions are mounted, held against rotation by means of a hexagonal sleeve 20 on which the plate I9 is mounted fitting in a hexagonal opening in the tubular pilot and arlng gear 2| meshing with the pinions I8 and secured to the cutter head I4 whereby the cutter head is rotated at a reduced speed as compared with the shaft Il and in the opposite direction. In practice, I have found that a gear reduction of about 3 to 1 gives satisfactory results.

'I'he cutter head I4 comprises a sleeve portion 22 having a nice running iit on the pilot, whereby the cutter head is accurately centered with respect to the pilot, which, in turn, is accurately centered with respect to the valve stem guide. This cutter head sleeve 22 may be secured to the ring gear 2| by means of a bayonet joint connection 23, a set screw 24 being provided to prevent disconnection of this bayonet joint. The ring gear 2| may be secured to a bearing cap 2l by means of suitable screws 29. A suitable antifricticn bearing may be provided between the bearing cap 25 and the extended hub 21 of the pinion I1. r

The inner raceway 28 of the anti-friction bearing may be clamped in place between the planet pinion retaining plate 29 and a bearing lock nut 30 threaded onto the extended hub 21 of the center pinion I1. The operating shaft I6 has a bayonet joint connection 3| with this extended hub 21 so that the cutter head and gear reduction assembly may be slipped into place from the inside of the cylinder, and the operating shaft I6 may be slipped into place from the outside of the cylinder and readily engaged with the extended hub ofthe pinion by reason of the'f aforesaid bayonet joint connection 3|. The bayonet joint connection is so designed that the rotational operating movement of the shaft will hold it in connected position. 'I'he shaft may be readily disconnected from the cutter head simply by rotating it backward far enough to enable the bayonet joint to be disconnected.

For feeding the cutter head toward the valve seat, the feed nut I4 is turned by hand in a direction to press it against the anti-friction bearing 32 provided between the feed nut and the hub 33 of the operating handle I5. It is cus-. tomary to grind two different zones of the valve seat at different angles. This is accomplished by pairs of cutters 34, 35, having different degrees of angularity with respect to the axis of the valve seat. This provides a relatively narrow zone on which the finishing cutter hereinafter referred to operates in order to provide a smooth narrow zone on which the conical valve may seat perfectly.

The next step is the finishing operation shown in Fig. 5 which involves simply the substitution of a finishing cutter head 36 for the roughing cutter head shown in Fig. 4. 'I'his finishing cutter 36 may be of the type having irregularly spaced cutting teeth of different slopes, some having positive rake and others negative rake, and some of the cutting edges being righthand spirals and others being left-hand spirals. The finishing cutter head is accurately centered on the tubular pilot which, in turn, is accurately centered in the valve stem guides so that the valve seat will be finished accurately and coaxially with respect to the valve stem and in a plane at right angles with respect thereto. The finishing cutter 36 may have a bayonet joint connection with the ring gear 2| and be held in place by the set screw 24.

In Fig. 5 the apparatus is shown installed in position for resurfacing one of the valve seats of a known type of airplane motor cylinder mounted in a special vise for holding the work in coni venient position for operation. This vise comprises a base 31 which may be adjustably mounted to swivel about a clamping bolt 33 and an annular supporting flange 33 carried by the base against which the annular flange 4,0 of the cylinder is clamped by means of hook-shaped clamping bolts Il. By means of the two swivel adiustments, the cylinder can be mounted in any desired position which will be most convenient for the operation of the reseating apparatus. If desired, a swivel bracket I2 for a lamp socket may be provided so that the lamp can be swung from a position in which it will illuminate the interior of the cylinder to a position out of the way of the cylinder in which easy access may be had for the insertion of the pilot and cutter head.

T'he use of the apparatus has been outlined in connection with the description of the various apparatuses successively employed. To recapitulate the first step is the cleaning and scraping of the valve stem guide 2 and the counterboring of the ends of the guide, as shown in Fig. 2. 'I'hese counterbores are coaxial with respect to the valve stem guide because of the centering effect of the scraping and cleaning shank 3.

The next step is the insertion of the pilot and feed mechanism shown in Fig. 3, the pilot Il being accurately centered by means of the counterbores previously formed. The next step is the putting in place of the roughing cutter head and the operating mechanism therefor shown in Fig. 4, and the operation of this rough- 'ing cutter mechanism to finish the valve seat roughly by providing two conical zones of different slopes. The next step is the putting in place and operation of the finishing cutter head shown in Fig. 5.

It will be seen that the above-described use of this apparatus results in a smoothly finished valve seat ground coaxially with respect to the valve stem guide and in a general plane at right angles with respect to the valve stem guide, thus providing a leakless valve seat and preventing the undesirable effects of excessive temperature in the motor head, excessive wear of the valve and valve seat because of the blow torch action of the hot gases, and excessivel oil and gas consumption.

Further modifications will be apparent to those skilled in the art, and it is desired, therefore, that my invention be limited only by the prior art and the scopeV of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide, a surface cutter having an opening into which said tubular pilot extends for centering the Cutter, and means for rotating said cutter comprising a shaft extending through said tubular pilot, and speed reduction gearing effective between said shaft and cutter.

2. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide, a surface cutter having an opening into which said tubular pilot extends for centering the cutter, and means for rotating said cutter comprising a shaft extending through said tubular pilot, and speed reduction gearing effective between said shaft and cutter, including gearing mounted on said pilot.

3. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide. a surface cutter rotatably mounted on said pilot, and means for rotating said cutter comprising a shaft extending through said tubular pilot, and speed reduction gearing effective between said shaft and cutter, including a gear rotatablewith said shaft,- gearing mounted on said pilot and meshing with said gear, and a gear rotatable with said cutter and meshing with said gearing.

4. A valve seatsurfacing apparatus comprising a tubular pilot for4 extending through a valve stem guide, a surface cutter having an opening into which said tubular pilot extends for centering the cutter, means for rotating said cutter comprising a shaft extending through said.

tubular pilot, and feed means for said cutter on the opposite side of the guide from the cutter.

5. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide, a valve seat surfacing tool, said tool having an opening into which said tubular pilot extends for centering the tool, and means for rotating said tool comprising a shaft extending through said tubular pilot.

6. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide. a valve seat surfacing tool, said tool having an opening into which said tubular pilot extends for centering the tool, means for rotating said tool comprising a shaft extending through said tubular pilot, and feed means for said tool on the opposite side of the guide from the'tool comprising a feed nut surrounding said shaft for moving said shaft axially.

7. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide, a valve seat surfacing tool, said pilot having a cylindrical portion and said tool having a portion surrounding said cylindrical portion and rotatably mounted thereon, and means for rotating said tool comprising a shaft extending through said tubular pilot.

8. A valve seat surfacing tool comprising a tubular pilot for extending through a valve stem guide and the valve port associated therewith substantially in coaxial alignment with the valve scatto be surfaced, a stationary bearing surface carried by a portion of said pilot adjacent said valve seat for rotatably supporting and centering a cutter head, and drive means for rotating a. cutter head on said stationary bearing surface, the latter means comprising a shaft extending through said tubular pilot.

9. A valve seat surfacing tool comprising a tubular pilot for extending through a valve stem guide and the valve port associated therewith substantially in coaxial alignment with the valve seat to be surfaced, a stationary bearing surface carried by a portion of said pilot adjacent said valve seat for rotatably supporting and centering a cutter head, a cutter head mounted on said stationary bearing surface, and drive means for rotating said cutter head, said drive means comprising a shaft extending through said tubular pilot.

10. A valve seat surfacing tool comprising a tubular pilot for extending through a valve port in coaxial alignment with the valve seat to be surfaced and into a valve stem guide in substantially fixed relation therewith, a stationary bearing surface carried by a portion of said pilot adjacent said valve seat for rotatably supporting and centering a cutter head, and drive means for rotating a cutter head on said stationary bearing surface, the latter means .comprising a shaft extending through said tubular pilot.

11. A valve seat surfacing tool comprisinga tubular pilot for extending through `a valve port in coaxial alignment with the valve seat to be surfaced and into a valve stem guide in substantially fixed relation therewith, a stationary bearing surface carried by a portion of said pilot adjacent said valve seat for rotatably supporting and centering a cutter head, a cutter head mounted on said stationary bearing surface, and drive means for rotating said cutter head comprising a shaft extending through said tubular pilot. p

12. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide and valve port associated therewith, a valve seat surfacing tool, said pilot and said tool having substantially complementary interiltting portions for centering the tool, and means for rotating said tool comprising a shaft extending through said tubular pilot.

13. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide and a valve port associated therewith, a valve seat surfacing tool comprising a rotary cutter head and a cutting tool, said rotary cutter head having an opening into which said tubular pilot extends for centering the tool, and means for rotating said rotary cutter head comprising a shaft extending through said` tubular pilot.

14. A valve seat surfacing apparatus comprising a tubular pilot for extending through a valve stem guide and a valve port associated therewith', a valve seat surfacing tool comprising a rotary cutter head and a cutting tool, said rotary cutter head and said pilot having substantially complementary intertting portions for centering the cutter head, and means for rotating said cutter head comprising a shaft extending through said tubular pilot.

15. Apparatus for resurfacing valve seats of radial type' motors having inwardly facing valve seats in the head of the cylinder and having tubular valve stem guides lying farther from the cylinder than the valve seats comprising a tubular pilot for insertion through a tubular valve stem guide and extending a substantial distance beyond said tubular guide on the valve seat side thereof, a bearing carried by saidtubular pilot extension substantially beyond said tubular valve stem guide on the valve seatside of said guide,

a valve seat surfacing device rotatably supported on said bearing, and means for rotating said valve seat surfacing device comprising a shaft extending through said tubular pilot.

16. Apparatus for resurfacing valve seats of radial type motors having inwardly facing valve seats in the head of the cylinder and having tubular valve stem guides lying'farther from the cylinder than the valve seats comprising a tubular pilot for insertion through a tubular valve stem guide and extending a substantial distance beyond said tubular guide on the valve seat side thereof, a bearing carried by said tubular pilot extension substantially beyond said tubular valve stem guide on the valve seat side of said guide, a valve seat surfacing device rotatably supported on said bearing, means for rotating said valve seat surfacing device comprising a shaft extending through said tubular pilot, and means for feeding said valve seat surfacing device axially.

17. Apparatus for resurfacing valve seats of radial type motors having inwardly facing valve seats in the head of the cylinder and having tubular valve stem guides 'lying farther from the cylinder than the valve seats comprising a tubular pilot for insertion through atubular valve stem guide and extending a substantial distance beyond said tubular guide on the valve seat side thereof, a raceway and multlrotor antifriction bearing carried by said tubular pilot extension substantially beyond said tubular valve stem guide on the valve seat side of said guide, a valve seat surfacing device rotatably supported on said bearing, and means for rotating said valve seat surfacing device comprising a shaft extending through said tubular pilot.

18. Apparatus for resurfacing valve seats of radial type motors having inwardly facing valve seats in the head of the cylinder and having tubular valve stem guides lying farther from the cylinder than the valve seats, comprising a pilot insertable into said tubular valve stem guide and having a portion extending a substantial distance beyond said guide toward said valve seat, a valve scat surfacing tool rotatably mounted on said extension of said pilot whereby said surfacing tool is laterally supported thereby beyond the inner end of the tubular valve stem guide on the valve seat side of the guide, a shaft extending into said cylinder for effecting rotation of said device, and speed reduction gearing between said shaft and device comprising a gear driven by said shaft rotatable with said device and supported by said pilot extension.

19. Apparatus for resurfacing valve seats'of radial type motors having inwardly facing valve seats in the head of the cylinder and having tubular valve stem guides lying farther from the cylinder than the valve seats, comprising a pilot insertable into said tubular valve stem guide and having a portion extending a substantial distance beyond said guide toward said valve seat, a valve seat surfacing tool rotatably mounted on said extension of said pilot whereby said surfacing tool is laterally supported thereby beyond the inner end of the tubular valve stem guide on the valve seat side of the guide, a shaft extending into said cylinder for effecting rotation of said device, speed reduction gearing between said shaft and device comprising a gear driven by said shaft rotatable with said device and supported by said pilot extension, and means for feeding said device axially.

20. Apparatus for resurfacing valve seats of radial type motors having inwardly facing valve seats in the hea'd of the cylinder and having tubular valve stem guides lying farther from the cylinder than the valve seats, comprising a pilot insertable into said tubular valve stem guide and having a portion extending a substantial distance beyond said guide toward said valve seat, a raceway and multlrotor antifriction bearing mounted on said extension, a valve seat surfacing tool rotatably supported by said antifriction bearing, whereby said surfacing tool is laterally supported thereby beyond the inner end of the tubular valve stem guide on the valve seat side of the guide, a shaft extending into said cylinder for effecting rotation of said device, and speed reduction gearing between said shaft and device comprising a gear driven by said shaft rotatable with said device and supported by said pilot extension.

HARRY G. MILLER. 

